Power Management Unit (PMU), in general is used to control power applied to an electrical load depending on load conditions and/or input power applied to the system. PMUs are implemented using solid-state device such as BJTs or FETs and capacitors and/or inductors. PMUs are switching regulators capable of boosting or bucking a DC input voltage applied to them.
Microbial Fuel Cells (MFC) are used to generate electricity while treating waste-water. Microbial Electrolysis cells (MEC) are used to produce hydrogen gas from waste-water by applying external power to it.
PMUs have been used to control the output power based on the power generating capabilities of the microbial fuel cell. MFC and MEC coupled systems are low-voltage systems (around 1V) and low current in the order of few hundred mA. Hence, the PMUs require electronic switches and other associated circuitry capable of operating under such low voltages and producing very little voltage drop across them.
Carbon Nanotubes and nanowires are used to improve charge transfer between anaerobic bacteria and anode surface of a microbial fuel cell.
Inverters together with PMUs and/or DC combiners are used to apply power to the electrical grid or local factory such as waste-water treatment plant either from an array of solar panels, stack of solid-oxide fuel cells using natural gas or other fuels, and farm of wind turbines.